Oct. 17, 2012 -- Extreme agitation, aggressiveness, and psychosis are common among people with Alzheimer's disease -- especially in its later stages -- and they are among the symptoms most often associated with admission to nursing homes.

Antipsychotic drugs are often prescribed to treat these symptoms, but their use remains controversial.

Federal regulators recommend that patients take the drugs for no more than six months, but new research published online today in the New England Journal of Medicine questions the wisdom of abruptly stopping treatment.

People with Alzheimer's whose symptoms improved while taking the antipsychotic drug risperidone (Risperdal) had a high risk for relapsing when taken off the medication.

The study suggests that the common practice of arbitrarily ending treatment after a few months may cause harm to patients, says researcher D.P. Devanand, MD, of the New York State Psychiatric Institute and Columbia University.

"Antipsychotic drugs don't work for all patients," Devanand says. "But for those who do respond, it is important to use caution and watch for relapses when they are taken off them."

Symptoms Returned in 60% of Patients

The initial phase of the study included 180 Alzheimer's patients with symptoms of agitation, aggression, or psychosis. They were treated with risperidone for four months.

The second phase of the study, which lasted an additional eight months, included 110 patients whose symptoms improved while taking risperidone.

A third of the patients remained on risperidone for the eight additional months, while another third took risperidone for four months, followed by placebo for four months.

The rest took the inactive placebo pills for the duration of the trial, and after four months these patients had nearly double the risk of relapse as those who remained on risperidone (60% vs. 33%).

During the second four months, around half of the patients who switched from risperidone to placebo relapsed, compared to 15% of those who continued to take risperidone.

Antipsychotics Linked to Death

The findings suggest that relapses are common following stoppage of antipsychotic drug treatments.

But important safety questions remain about the use of the drugs in Alzheimer's patients, Devanand says.

Treatment with antipsychotic drugs has been linked to a higher risk of death in several studies. Antipsychotics also carry a boxed warning that elderly people with dementia-related psychosis treated with antipsychotic drugs have a higher risk of death.

"The question remains: Does the risk of relapse outweigh the risks associated with taking these drugs?" he asks.

Jeffrey A. Lieberman, MD, chairs the department of psychiatry at Columbia University, but he was not involved with the study.

He says there is an urgent need for better, safer drugs to treat aggression, agitation, and psychosis in people with Alzheimer's disease.

"Even the most loyal and devoted caregivers can quickly become overwhelmed when dealing with these symptoms," he says. "This is often the point when they feel that a nursing home is their only choice."

Lieberman agrees that important safety questions remain, but he says the new study confirms that treatment with antipsychotic drugs can improve symptoms in many people with Alzheimer's disease.

"In general, physicians have become more reticent about prescribing these drugs to Alzheimer's patients, even though they have nothing to replace them with," he says. "This study should provide reassurance, but it also shows that not all patients respond."

He adds that when the drugs are prescribed, patients must be followed carefully.

The study was funded by a grant from the National Institutes of Health and the Department of Veterans Affairs.